The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 17-50mm f2.8 XR II VC LD and the Sigma 18-35mm F1.8 DC HSM for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is a crucial factor to consider when comparing two lenses. Sigma 18-35mm F1.8 DC HSM is the longer of the two lenses at 121mm. The Tamron 17-50mm f2.8 XR II VC LD with a length of 95mm, is 26mm shorter. On the other hand, the Tamron 17-50mm f2.8 XR II VC LD has a larger diameter of 80mm compared to the Sigma 18-35mm F1.8 DC HSM's 78mm diameter.
The weight of a lens is equally significant as its external dimensions, particularly if you intend to handhold your camera and lens combination for extended periods. Tamron 17-50mm f2.8 XR II VC LD weighs 570g, which means it is 240g (29%) lighter than the Sigma 18-35mm F1.8 DC HSM which has a weight of 810g.
Below you can find the dimension and weight table of the Standard Zoom Lenses in Nikon F (DX) Mount for size comparison purposes.
Standard Lenses in Nikon F (DX) Mount for Size Comparison
Filter Threads
Both the Tamron 17-50mm f2.8 XR II VC LD and the Sigma 18-35mm F1.8 DC HSM have the same Filter thread size of 72mm.
Below are links to the 72mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Tamron 17-50mm f2.8 XR II VC LD and the Sigma 18-35mm F1.8 DC HSM has the same Nikon F (DX) lens mount. Some of the latest released cameras that are compatible with the Nikon F (DX) lenses are Nikon D3500, Nikon D7500 and Nikon D5600.
Tamron 17-50mm f2.8 XR II VC LD is also available in Canon EF mount.
Sigma 18-35mm F1.8 DC HSM is also available in Canon EF , Pentax KAF, Sony Alpha and Sigma SA mounts.
Focal Range
Tamron 17-50mm f2.8 XR II VC LD has a focal range of 17-50mm and
2.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
25.5-75mm when used on a APS-C / DX format camera.
On the other hand, the Sigma 18-35mm F1.8 DC HSM has a focal range of 18-35mm and 1.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-52.5mm when used on a APS-C / DX format camera.